The teachings of all of the references cited herein are incorporated in their entirety herein by reference.
A number of fermentation methods have been developed to produce recombinant polypeptides such as recombinant (r) (h) factor XIII in yeast. [See Bishop et al. Biochem. 29:1861 (1990).] While yeast tends to be a good host cell to produce many recombinant proteins, to obtain high yields of the polypeptide, it has been necessary to add yeast cell extract to the fermentation medium. However, yeast extract is expensive. Prior art efforts to produce a fermentation medium that does not contain yeast cell extract have been disappointing because the resultant yields of the recombinant protein are drastically reduced. Thus, there is a need to produce a yeast cell culture medium that does not contain yeast cell extract, but that can nonetheless be used to produce recombinant proteins in yeast resulting in high yields of the recombinant protein.